Apparatus for molding hollow articles



April 21, 1925.

T. E. MURRAY APPARATUS FOR MOLDING HOLLOW ARTICLES Filed Sept. 13 1924anoenboz 777OI77Q6 5 War/a5 Patented Apr. .21, 1925.

' UNITED STATES PATENT OFFICE.

THOMAS MURRAY, '0' BROOKLYN, NEW'YORK.

AZPIFE'ARAYTUS r03. MOLDING HOLLOW ARTICLES.

Application filed September 13, 1924.. Serial No. rear/2.

application I have described an apparatus which can be used forproducing short transportable sections of such conduits. The presentapplication is in part a division. of the aforesaid application and isdirected to the making of comparativelyshort sections of conduit and tothe making of a variety of other articles of concrete and similarplastic materials; such, for example,

block to be molded.

as poles, planks, railroad ties, hollow bricks or blocks forthe-building of floors, walls andpartitions and for the building ofconduits for the distribution of fluids and similar uses. v

The -accompanying drawings illustrate embodiments of the invention.

Fig. 1 is a-perspective view of a block molded inaccordance with thisinvention.

Fig. 2 is aperspective view illustrating the method of molding suchblocks.

Fig. an alternative arrangement, shown in perspective, ,ior moldingsuch.

blocks.

of ducts greater than two,jan'd is particularly useful in makingarticles having a multiplicity of ducts rather than a single one.

The blocks are molded in a trough or box 3 open at the top, the depth ofwhich corresponds substantially to the thickness of the The cores 4c arecarried in the box in position to form the ducts 9. These coresarepreferably of thecharacter described in my application No. 670,423,highly resilient rubber tubes with walls of sufiicient thickness andstrengthto support the external pressures, and adapted when pulledendwise to contract transversely and break the adhesion of the rubber tothe surrounding concrete so as to permit their withdrawal by continuedlongitudinal pulling. Cores ofth-is sort are provided of a lengthcorresponding to that of a considerable number of the sectional blocks1, and are used for molding a number of such blocks at once, so as tosecure uniformity in the several blocks and to lessen the work involvedin setting up and withdrawing the cores of a number of blocks by doingthese things for .all the blocks at a single operation. The cores passthrough properly spaced holes in. bulkheads or partitions 7, extendingacross the box at intervals and held by grooves (S in the side walls ofthe box engaging tongues on the side edges of the partitions. The cores4i makea snug lit in the holes in the partitions through which theypass; and the ends of the cores (not shown) may betastened in any way toan end wall oi the box. The parts being set up. as illustrated in Fig.1, concrete 7 is poured from a chute or nozzleS into the successivecompartments in the, box, filling them to the top. The excess may bescraped off with a straight edge (andtamped if a dense product isdesired) or the exposed side may be finished in any desired way.

\Vhen the concrete is sufiiciently hard the cores 4: are withdrawn bypulling the-m longitudina-lly. The molded. blocks can then.

be pushed up from below, either with the partitions or without thesepartitions. Or

.therpartitions may first be pushed out from below and the concreteblocks afterwards. A "false bottom or any one or various other knownexpedients may be used for lifting the molded blocks out of the box.

Fig. 3 illustrates the use of the invention in connection with a movableshield similar to thatdescribed in my previous application No. 722,913.Here the forward portions of the cores & are carried in tubes 9 in asort of shield with a front wall 10 and a rear wall 11. The tubes 9project through the rear wall 11 of the shield, as indicated, and arepassed through openings in a series of bulkheads or partitions 12. Theside walls of the box 1 are formed with openings 13 in their upper edgesat certain intervals. T-shaped'brackets 14 are arranged to slide on theside walls of the box and length.

carry pins 15 which may be dropped into vanced and the partitions arecaught in succession by brackets 14 placed at intervals along the sides;While the concrete is being poured into the mold thus formed be tweenthe partitions 12 and 12 theshield can be moved forward until the nextpartition 12 arrives at the desired point, where it will be clamped bymeans of brackets 14, sothat the filling of concrete may proceed in thespace imn'iediately behind it while the shield and the other partitionsare tak ing a further step forward. 13 are set so close together thatthe partitions may be fastened at intervals of varying length, dependingon the length of the core which. will hold itself substantially straightwhen supported at the ends. of course, the partitions can be set closerif it be desired to make the blocks of less This arrangement has someadvantages over the simpler arrangement of Fig. 2. It is easier tolocate the partitions 12 on the extendedends of the metal tubes 9 thanit is to locate them 011 a rubber tube. lVhen a partition, as 12, isfastened in place and the shield moved on to pull the rear ends of thetubes 9 out of the partition, the cores 4 will fit the holes in thepartition with suliicient closeness to prevent the passage of theplastic material.

The shape ofthe box, which forms the outside of the molded article, canbe straight or curved or of various irregular shapes. The flexibilityoi": the cores. makes it possible also to bendthem around to form curvedducts. And where a plurality of cores are used they may be parallel ormay converge according to the particular design otthe block and the ductrequired. In that case all the cores may be pulled out at one operationas by clamping them to the shield in Fig. 3, or they may be pulled outseparately if that be more convenient; thus in building sections of amultiple-duct conduit all the cores may be pulled out of all the moldedsections at one operation, with a great saving of time. And,though theinvention may be applied to different styles of core, yet there arespecial advantages in simplicity and economy of production in the use ofsuch resilient tubular The openings The ,cores described may also be.used with variousother styles of mold and with partitions between thesuccessive molds whichare fixed instead of being movable like thoseillustrated.

Fig. 4 illustrates the making of hollow blanks or railroad ties or thelike and hollow circular poles. The mold box 15 has a rectangularopening or trough 16 extending lengthwise of it, and a semi-circulartrough 17. In theformer is a core 18 of highly resilient rubber, solidin the case illustrated, but it may be hollow if of sufficiently largesize. In the semi-circular trough is a semicircular core 19, with thecentral portion removed. The cores are held at intervals in their lengthby partitions or bulkheads similar to those in Figs. 1 and 2. A cover20,

preferablymade in sections, is removed during the pouring operation. Thetroughs are filled and levelled off and thecover laid on to secure aneven finish on the upper surface. It will be understood, of course, thatthe trough 17 forms only a semi-circular segment of the post, two suchsegments being afterwards cemented together to make the finishedproduct. Ordinarily, where two or moreniolds or troughs are arrangedalong side of each other in a single structure they will be of the sameshape. I have illustrated diii'erent shapes in order to show thevariety. of products to which the invention is ap plicable. o v IAlthough I have described with greatparticularity of detail.certainembodiments of my invention, yetit is not to be understoodtherefrom that the invention is restricted to the particular embodimentsdisclosed. Va-

rious modifications may be made by those skilled in the art withoutdeparture from the invention as defined in the following claims.

What I claim is 1. An apparatus for molding a plurality of hollowarticles comprising a moldbox, partitions therein, and a core passingthrough the several partitions so that the same core serves in theseveral compartments sition during the casting of plastic materialaround it comprising means for supporting the core and a plurality ofseparate bulkheads at the rear of said supporting means adapted to beused in succession.

3. An apparatus for holding a plurality of cores properly spaced duringthe casting of plastic material around them, comprising means forsupporting said cores in proper relative positions and a plurality ofseparate bulkheads at the rear adapted to be used in succession. I

4. An apparatus'for molding hollow arti lit) cles comprising a pluralityof molds and a common core passing through said molds, said, core beingtubular, of sufiicient strength to support the external pressures and ofsuch a composition that when pulled it Will con tract transversely andseparate from the surrounding material so as to permit its Withdrawaland of such resiliency that when released it will resume its originalshape.

5. An apparatus for holding a core properly spaced during the casting ofplastic material around it, comprising means for supporting said core inproper positions and a plurality of separate bulkheads at the rearadapted to be used in succession.

6. An apparatus for holding a plurality of cores properly spaced duringthe casting of plastic material around them, comprising means forsupporting said cores in proper relative positions and a plurality ofseparate bulkheads at the rear adapted to be used in succession.

In Witness whereof I have hereunto signed my name.

THOMAS E. MURRAY.

